I didn't perform many comparisons against other APIs. Also,
performance has not been the main target. I mean, the
infrastructure for making it fast is there. The library contains
a small number of string handling functions that can be
optimized, leading to great speed improvements in all components.
But these functions hasn't been fully optimized yet.

About raw performance, the repository contains a simple
benchmarking driver which I use to track performance regressions
in the code. On my laptop, excluding the time needed to load the
input from disk, I can easily process XML with speeds over
50MB/s, which looks like a good start.

Easy win comparisons: this library is way faster than Java's
built-in XML library and also way faster than the current Phobos
std.xml API.